1. Field of the Invention
The invention relates to a device for displaying cartographic information, comprising a memory for storing cartographic data, a location-determining unit and a display. In this context cartographic data are understood to be data such as: maps showing roads, data on the category of roads and junctions, locations of traffic lights, priority laws in force, speed restrictions and other traffic do's and don'ts, road names, traffic signs, signposts and zebra crossings, in short "road furniture", as well as petrol stations, hotels, restaurants and the like ("facilities") and prominent landscape features ("landmarks").
The invention also relates to a navigation system provided with the device, a vehicle provided with the navigation system and a method for displaying cartographic information on a display of a navigation system, which repeatedly determines a current position of a vehicle in relation to a road map stored in digitalized form and navigates the vehicle along a predetermined route.
2. Description of the Related Art
A device of this type is disclosed in the European Patent Application 0 355 232 A2. This application describes a device for displaying a section of a road map, only the route to be followed according to a navigation system being displayed, part for part, with the associated side routes (see FIGS. 1, 5, 15). Road sections can be rotated, magnified or reduced. A device of this type has the disadvantage that at a junction no specific information is given on the nature of the junction. A user is therefore obliged to make an instant on-the-spot evaluation of every traffic situation which requires a decision on his or her part.
German Offenlegungsschrift (German published specification) DE-3905493-A1 describes a navigation system with which a section of a road map is displayed showing the route to be followed (see FIG. 3). Abstract navigation symbols can also be shown at junctions (see FIGS. 4, 5, 6). However, these symbols, which are also known as pictograms, are so general that they can be used only for a small number of standard traffic situations. Moreover, standard traffic situations of this type are often clear and the additional information is therefore superfluous.